Resistant bacteria decline sharply after hospital unit renovated

Researchers observed a sharp but temporary decline in patient colonization with vancomycin-resistant enterococci, or VRE, in the year following an extensive renovation of a Salt Lake City hospital unit, likely because contaminated surfaces had been replaced.

There is a well-established relationship between hospital construction and nosocomial infections, according to Clyde D. Ford, MD, physician in the Blood and Marrow Transplant Program at Latter Day Saints Hospital, and colleagues.

“In contrast to infections occurring during construction, little attention has been directed to the potential beneficial effect of renovation on infection risk after the completion of the renovation,” Ford and colleagues wrote in Infection Control and Hospital Epidemiology.

According to their study, VRE is one of the bacterial pathogens with potential to contaminate the surfaces in patient rooms, leading to an increased risk of colonization and infection.

“Thus, remodeling that includes replacement of surfaces could conceivably reduce the rate of infection, at least until environmental recontamination occurs,” they wrote.

VRE gastrointestinal colonization is common in the unit where Ford and colleagues work, they said. The unit, which cares for patients with hematologic malignancies and recipients of hematopoietic stem-cell transplantation, was extensively remodeled one half at a time between January 2009 and April 2010, and all surfaces in patient rooms, hallways and staff working areas were replaced.

For their study, Ford and colleagues recorded incidences of VRE colonization in patients before, during and after the unit was remodeled. In the 2 years before remodeling, colonization rates were stable at 15.8 cases per 1,000 inpatient days. The rate was 8.7 cases per 1,000 inpatient days during construction and dropped to 4.4 cases per 1,000 inpatient days during the first year after renovation, with an HR of less than 0.23 (95% CI, 0.18 to 0.44).

Eventually, the rate of VRE colonization returned to near baseline levels in the second and third years after construction, according to Ford and colleagues. However, the dominant strains of VRE that were present before the unit was remodeled disappeared and were replaced by new strains, they said.

They reported no known changes in risk factors for VRE colonization and said environmental samples taken from outside patient rooms revealed several contaminated areas commonly touched by personnel.

“Our data show a substantial transient decrease in VRE colonization after the renovation,” Ford and colleagues wrote. “We hypothesize that this is due to the replacement of contaminated surfaces, resulting in reduced colonization rates among patients that, in turn, minimized the recontamination of the environment.”

In a recent study published in Science Translational Medicine, researchers tracked the microbial ecosystem of a newly constructed hospital. Known as the Hospital Microbiome Project, they collected microbial samples from the University of Chicago’s Center for Care and Discovery 2 months before the facility opened on Feb. 23, 2013, and continued collecting samples for a year thereafter.

Among other findings, the researchers discovered that on a patient’s first day in the hospital, bacteria in the room typically moved from surfaces toward the patient. However, the patient’s own microbial signatures influenced the room microbiota over time, the researchers said, and within 24 hours, most bacteria began to move in the other direction from the patient to the room, particularly the bedrails. In addition, an analysis of patients with longer hospital stays and the rooms that they occupied for multiple months showed that some potentially harmful bacteria such as Staphylococcus aureus and Staphylococcus epidermidis managed to acquire antibiotic resistance genes. These genes were consistently more likely to be found on room surfaces than on patients. – by Gerard Gallagher

References:

Ford CD, et al. Infect Control Hosp Epidemiol. 2017;doi:10.1017/ice.2017.138.

Lax S, et al. Sci Transl Med. 2017;doi:10.1126/scitransmed.aah6500.

Disclosure: One researcher reports receiving research support from Cubist/Merck for an unrelated project.